A reliable, fast and low cost maximum power point tracker for photovoltaic applications J.M. Enrique * , J.M. Andu ´jar, M.A. Boho ´ rquez Departamento de Ingenierı ´a Electro ´ nica, de Sistemas Informa ´ ticos y Automa ´ tica, Universidad de Huelva, Spain Received 19 February 2009; received in revised form 22 July 2009; accepted 16 October 2009 Available online 14 November 2009 Communicated by: Associate Editor Elias Stefanakos Abstract This work presents a new maximum power point tracker system for photovoltaic applications. The developed system is an analog version of the “P&O-oriented” algorithm. It maintains its main advantages: simplicity, reliability and easy practical implementation, and avoids its main disadvantages: inaccurateness and relatively slow response. Additionally, the developed system can be implemented in a practical way at a low cost, which means an added value. The system also shows an excellent behavior for very fast variables in incident radiation levels. Ó 2009 Elsevier Ltd. All rights reserved. Keywords: Analog system; Efficiency; Low cost; Maximum power point tracker; Photovoltaic array; “P&O” algorithm 1. Introduction In the specialized literature numerous proposals of MPP tracking systems can be found. Most of them have similar efficiency, which can also be considered acceptable for most applications. As a result, the interest of the authors when implementing this work has focused on achieving a certain added value in the proposed system, which can be found in the accurateness, speed and low cost. This allows its appli- cation even to household installations, where investment costs may be the most determining factor for decision mak- ing. The developed system presents the advantage of its high speed which also helps to improve the photovoltaic system efficiency. A photovoltaic (PV) array that functions under uniform radiation and temperature conditions presents an I–V and P–V characteristic as the one shown in Figs. 1(a) and (b), respectively. As can be observed, there is a single point, called “MPP” (Maximum Power Point), where the array provides the maximum power possible for these environ- mental conditions (radiation and temperature), and so functions with the maximum performance. When a load is connected directly to a PV array (direct coupling), the operation point is defined by the intersection of its I–V characteristics, as shown in Fig. 1(a). In general, this operation point does not coincide with the MPP. Thus, in direct coupling systems, the array must be over-dimensioned to guarantee the power demand of the load. Obviously, this implies a more expensive system. To solve this problem, a DC/DC (Xiao et al., 2007) converter with an algorithm for the automatic control of its duty cycle “d” is inserted between the photovoltaic array and the load (see Fig. 2), resulting in what is known as MPPT (Maximum Power Point Tracker) system. The MPPT must control the voltage or current (through the d of the converter) of the PV array regardless of the 0038-092X/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.solener.2009.10.011 * Corresponding author. Address: Departamento de Ingenierı ´a Electro ´- nica, de Sistemas Informa ´ticos y Automa ´tica, Universidad de Huelva, Huelva, Spain. Tel.: +34 959 217374/7656/7671; fax: +34 959 217348. E-mail addresses: juanm.enrique@diesia.uhu.es (J.M. Enrique), andu jar@diesia.uhu.es (J.M. Andu ´ jar), bohorquez@diesia.uhu.es (M.A. Bo- ho ´ rquez). www.elsevier.com/locate/solener Available online at www.sciencedirect.com Solar Energy 84 (2010) 79–89